Control device



June 16, 1936. L. w. EGGLEsToN ET A1. '2,044,729'

CONTROL DEVICE Filed March 6, 1933A f [mhh nl; 2'? v' MW" I z. Illllff Patented June 1,6, 1936 PATENT OFFICE CONTROL DEVICE Lewis W. Eggleston and Earnest J. Dllman, Detroit, Mich., assgnors to Detroit Lubricator Company, Detroit, Mich., a corporation of Michigan y Application March 6, 1933, Serial No. 659,664

6 Claims. (Cl. Z00-83) f "Our invention relates to new and useful improvements in control devices, and more particularly to a device responsive to temperature for controlling an electric circuit, for example.

An object of our invention is to provide a control device having a temperature responsive actuating means, the operation of which is regulated or controlled in accordance with variationv in a characteristic or condition of the atmosphere, such as temperature or barometric pressure.

Another object is to. provide a device of simple construction and which will operate efficiently.

The invention consists in the improved vconstruction and combination of parts, to be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawing, to be vtaken as a part of this specication, we have fully and clearly illustrated a preferred embodiment of our invention, in which drawing- Figure 1 is a top plan view of the control device embodying our invention, but with the cover member and certain temperature responsive operating means removed;

Fig. 2 is a view in section on the line 2-2 of Figure 1, but showing the cover and temperature responsive operating means in position, and

Fig. 3 is a view in end elevation, but showing the cover member in section...

Referring .to the drawing by characters of reference, I designates a base or back member which is substantially rectangularY and preferablyof insulating material. Adjacent one end of the base member there are laterally spacedv bosses 2, 3. A plate member 4 of resilient sheet metal is secured to the top faces of and extends between the bosses 2, 3. The member 4 is rigidly secured to'the bosses 2, 3 by screws 4a andis provided between the bosses 2, 3 with substantially parallel end slots 5, 6 which receive the upwardly projecting arms or poles 1. of a U-shaped permanent magnet 8. The plate member 4 has a tongue portion 9 formed between the slots 5 and 6, which extends between-the arms or magnet poles 1. The plate portion 9 is secured to the magnet by a rivet, or the like, I so that the plate member 4 supports the magnet 8. The

rivet I D also secures one end of a supporting bar or member II to the magnet 8 and plate member 4. The supporting member II extends longitudinally of the base member in substantially parallel loverlying relation thereto and is preferably provided with depending side anges I2 which make the member I I substantially rigid. The member 4 serves as a hinge or fulcrum for the member II and flexibly connects the member Il to the base member I. The member Il is also secured to the plate member 4 by a screw 5 I3 which also extends through and serves to hold a contact supporting block I4 in position between the members 4 and Il. The block I4 is preferably slotted at one end, as at I4, to receive a contact member I5 which projects through the plate member 4 and the supporting bar II, being adjustably. screw-threaded therein. The supporting bar Il has secured adjacent its free end a switch` blade or contact carrying arm I6 which extends toward and into overlying relation to the magnet 8 and is provided with a contact member I1 cooperable with the contact member I5. The end portion I8 of the blade I6 which overlies the magnet 8 serves as an armature for cooperation with the magnet poles l. The blade I6 isv secured to the supporting member II by screws I9, or the like, the blade being insulated from the supporting member by a sheet of insulating material 20. The blade I6 is provided with a permanent set or is bent upwardly from the supporting member II, as at 2 01, adjacent the screws I9 so that the contact I1 is normally out of engagement with the contact member I5 by the inherent resilience of the blade. At the sides of the supporting member I I there are longitudinally spaced supporting posts 2| rigid with and rising from the base member I. A plate member 22 is secured. to and seats upon the top 'ends of the posts 2l and overlies the blade I6,

being substantially parallel with the base member I. Supported by the plate member 22 and by the posts 2l there is a power means 23 responsive to temperature for operating the switch blade I6. The means 23 preferably comprises a substantially cup-shaped container or casing having a marginal ange 24 which seats upon and is secured to the plate member 22. The container is provided with a movable wall 25 preferably formed by the head or end wall of an expansible-collapsible metal bellows 26 which is se- 45 cured and sealed at its other end, as at 21, to the inner periphery of an annular ilange 28 carried by a ring member 288 which its within and is sealed to the inside face of the container. The sealed space between the wall of the container and the bellows 26 provides an eXpansible-collapsible chamber 29. 'I'he chamber 29 is charged with a suitable volatile liquid` whichfon expansion and contraction due to changes in air temperature to which the means 23 is subjected will 55 move the end wall 25 relative to the plate member 22. The chamber 29 may be charged by means of the usual lling tube 529el which is then sealed by solder or other suitable means. 'I'he end wall 25 is provided with a plunger or operating member 39 of insulating material which extends downward through a guide aperture `3l in the plate member 22. The free end of the plunger has an axial extension or thrust rod 32 of reduced diameter providing on the plunger a downward facing shoulder 33 engageable with the .blade I6. The rod 32 extends through aligned apertures in the blade I6, the insulating plate 20, andthe supporting member II. The aperture through the supporting member I I is surrounded by a ilange 34 which serves to center or position one end of a coil spring 35 which abuts the underside of the member II and vseats vat'its other end in a recess 35a formed in the top o1' front face of the base member I. The spring 35 is held under compression between the Ibase member I and the supporting member II and normally tends to urge the supporting member and the blade I6 toward the temperature responsive means 23. The extent of movement of the supporting member |I by the spring 35 is determined by an adjustment screw 36 extending through the bar and insulating member 20 and adjustably threaded in a slotted insulating block 31 secured to the underside of the supporting member II by the screws I9. The adjustment screw 36 preferably abuts the underface of the plate member 22 between the posts 2|. Movement of the plungerl 39 by expansion of chamber 29 is opposed by a coil spring 38 held under compression and which seats at one end on the plate member 22 around the aperture 3| and at its other end engages the movable end wall 25. The thrust rod y32 projects through the member II and seats in la recess formed in the end face of a plunger or\operating member 39 which is positioned within the coil spring 35 and which. extends through a 'guide aperture 40 in the base member I.v Secured to the rear face of the base member I opposite the power means 23, there is a second power means having a cup-shaped container or casing 4Ivhaving a movable wall 42 preferably formed by the head or end wall of an expansible-contractible metal bellows 43 which is secured and' sealed at its other end, as at 43, to the inner periphery of a ange 44 vcarried by `a ringI member 44i1 which nts-within and is secured and sealed to the side wal-l of the container 4|. The plunger 39 extends into the bellows 43 and seats upon the end wall 42 for movement thereby. The container 4I and bellows 43 provide therebetween and within the container 4| a sealed expansible-collapsible chamber 45.

f The chamber 45 is in communication with a bulb element 46 by means of a tube 41 secured by a tting 48 to the container 4I. 'I'he chamber 45 and bulb 46 are charged with a suitable expansible-contractble uid, which may be either a liquid or a gas, which will be responsive to variations in a characteristic of the atmosphere.

The operation of our control device is as follows: The device is connected in a circuit to be controlled withone lead wire secured to the blade I6 at one of the screws I9 such that current will be transmitted through the blade i6 to the contact member l1. 'I'he other lead wire of the circuit is connected to the plate member 4 by one of the screws 4e with current flowing to the contact member I5 through the plate member 4 and supporting member il. 'The Screw 36 move the plunger 30 toward the blade I6 and the shoulder 33 into engagement therewith to ilex the blade against its inherent resilience, moving the armature I8 toward the magnet poles l. As the armature I8 is moved into the magnetic eld, the i'leld strength acting on the armature will increase and prior to the engagement of the contacts I'I, I5 the magnet poles 'I will overcome the resilient force of the blade I6 to make contact between the members I5 and Il with a quick and substantially snap action. The expansive force of chamber 29 acting on the plunger 39 to move the blade I6 to make contact is regulated by the opposing force exerted by the plunger 39. controlled by the fluid in the chamber 45. The chamber 45 may be charged with a gas such as nitrogen at atmospheric pressure so that the force acting on the plunger 39 will vary in accordance with changes. in atmospheric pressure. With the chamber -45 so charged, the operation of the plunger 30 by the temperature responsive means 23 will be compensated for changes .in atmospheric pressure'. Thus, any decrease in the atmospheric pressure acting on the wall :25 which would result in a greater pressure of the 'liquid in chamber 29 on the plunger 30 at a given temperature would be oifset or compensated by the The force exerted by the plunger 39 isopposing force of the iluid in the chamber `45 A Volatile liquidfin the chamber 45 and the bulb 46 will vary in accordance with the temperature surrounding-the bulb 46. 'I'he force acting on the plunger 30 due to the volatile liquid inthe chamber 29 will vary in accordance with the temperature surrounding the responsive means 23. .In order for the plunger 30 to be moved by the wall 25, the spring 38 must be overcome, the force of the spring 38 determining the differential between the forces acting on the plunger 39 and on the plunger 39 which must obtain in order for the plunger .3U to move the blade I6. The temperature surrounding the means 23 which will cause operation of the blade I6 to make circuit at a given temperature of the bulb .perature surrounding the bulb 46, because the force acting on the plunger 39 responsive to the temperature of bulb 46 determines the force which must be exerted by means 23 and therefore the temperature surrounding the means 23 which willovercome the force of plunger 39 and actuate the switch blade.

.llrrespective of whether the chamber 45 is 'charged with a gas or a volatile liquid, the dif- 75 ferential operation of the control device, that is, the difference in the number of degrees variation between making and breaking contact between the members I5 and Il, may be controlled by adjustment of the contact member I5. This variation in differential results from controlling the air gap between the armature I8 and the magnet poles 1; the closer the armature I8 to the magnet when contact is made, the greater will be the holding force of the magnet, and therefore the greater the differential. The range of the control device may be regulated by the adjustment screw 36 to vary the position of the blade I6 with respect to the shoulder 33 of plunger 30 so as to require greater or less expansion of the chamber 29 in order to move the blade I6. The spring l35 which resiliently supports the member l I not only cooperates with the screw 36 to regulate the positionpf the supporting member II and therefore of the blade I6 with respect to the plunger 30, but also serves as a safety means to permit overtravel of the plunger 30. If the plunger 30 continues to move after contact is made, the member II is free to move toward the base member I upon compression of spring due to the flexible plate member 4.

What we claim and desire to secure by Letters Patent of the United States is:

1. A control device comprising a base member -having an aperture therethrough, automatically actingpower means positioned on the opposite sides of said base member and -alined with said aperture, a supporting member pivotally mounted on said base member and having an aperture therethrough yalined with said rst-named aperture, a resilient switch blade secured to said supporting member and having an aperture therethrough `alined with said apertures, a contact member carried by said supporting member and cooperable with said blade, a thrust member extending through said apertures and operatively connecting said power means, and means on said thrust member engageable with and for actuating said blade,

2. A control device comprising a base member having an aperture therethrough, automatically acting power means positioned on the opposite sides of said base member and alined with said aperture, a supporting member pivotally mounted on said base member and having an laperture therethrough alined with said rst-named aperture, a resilient switch blade secured to said supporting member and having an aperture therethrough alined with said apertures, a contact member carried by said supporting member and cooperable with said blade, a thrust member extending through said apertures and operatively connecting said power means, a helical coil spring surrounding said thrust member and interposed between said base member and said supporting member whereby to permit overtravel of said thrust member, and means on said thrust member cngageable with and for actuating said blade.

3. A control device comprising a substantially flat plate member defining a base, an elongated supporting member pivotally secured at one end to said base and extending longitudinally thereof, a resilient sheet metal switch blade secured to said supporting member and extending toward said one end, a contact member carried by said supporting member and cooperable with'v 'said blade, said blade and said supporting member having alined apertures therethrough, said base having an aperture therethrough registering with said apertures, a thrust member extending through all of said apertures, said thrust member havinga shoulder in overlying engageable re- 4lationto and for actuating said switch blade, and

thransversely to said thrust member and positioned between said power means, means pivotally supporting said supporting member adjacent one of its ends, means to hold said supporting member in position relative to said base member, a movably mounted switch blade extending longitudinally of said supporting member and fixed thereto, 4a contact member carried by said supporting member and cooperable with said blade, and means on said thrust member engageable with and operable to actuate said blade.

5. A control device comprising a base member, a pair of opposed automatically acting power means carried by said base member, a separable thrust member positioned between and operatively connecting said power means, one part of said thrust member terminating in a reduced end portion longitudinally engaging the other `part of said thrust member, a supporting member positioned between said power means and having an aperture freely receiving said reduced portion such that said thrust member is reciprocatory relative to said supporting member, and a movable switch blade fixed to said supporting member and operable by said thrust member.

6. A control device comprising a base member, a pair of opposed automatically acting power means carried by said base member, a separable thrust member positioned between and operative- 1y connecting said power means, one part of said thrust member terminating in a reduced end portion longitudinally engaging the other part of said supporting member, and a movable switch blade fixed to saidsupporting member and positioned between said shoulder and said supporting member, said shoulder being operable to engage and actuate said blade.

LEWIS W. EGGLESTON. EARNEST J. DILLMAN. i 

